1. Field of the Invention
This invention generally relates to an input device inputting an instruction into a personal computer, and in particular, relates to an input device using a detection signal based on a position of a movable object moving along a given plane.
2. Description of the Related Art
Conventionally, an input device inputting an instruction by using position information of a movable object is known. This input device is, for example, connected to a computer and is used for inputting an instruction of an operator. In addition, input devices, which detect a position of a movable object by using a change of light or magnetic flux, are proposed conventionally. As to an art in which an amount of movement of a movable object is detected by using a change of light, Japanese Patent Application Publication No. 58-80517 (hereinafter referred to as Document 1) discloses, for example, a potentiometer having an optical emitter and an optical receiver respectively on both sides of a slit-having revolution body thereof and detecting a position of a movable object. Similarly, Japanese Patent Application Publication No. 1-125729 (hereinafter referred to as Document 2) discloses, for example, an optical position detecting device, which has an optical emitter and an optical receiver arranged at a fixed position and detects a position of a movable object having a slit. As to an art in which an amount of movement of a movable object is detected by using a change of magnetic flux, Japanese Patent Application Publication No. 63-240085 (hereinafter referred to as Document 3) discloses, for example, a magnetic potentiometer, which has a magnetic member and a magnetic flux detector arranged at a fixed position and detects a position of a revolution body having a slit.
The devices disclosed in Document 1 through Document 3 detect the movable object having a slit based on a change of light or magnetic flux. The devices only detect the amount of movement of the revolution body. On the other hand, an input device inputting an instruction into a computer, a car, a game machine or the like has a component changing an electrical resistance such as a volume switch. In the input device, a friction is generated when an operator changes the electrical resistance. That is, there is generated a load when the operator operates the device. It is thus different to operate the device minutely. These arts using a change of light or magnetic flux are used for position detection of a movable object. There is not provided an input device using the arts using a change of light or magnetic flux.